1. Field of the Invention
This invention relates to a vehicular safety arrangement for protecting a driver in a driver's seat of a vehicle during vehicle collision, and more particularly to improvements in the safety arrangement to improve impact energy absorption ability particularly when the driver is not restrained by a seat belt.
2. Description of the Prior Art
A variety of safety arrangements have been proposed and put into practical use as disclosed, for example, in Japanese Utility Model Provisional Publication Nos. 57-47477, 56-6668, and 56-16580 and Japanese Utility Model Publication No. 53-50978 and Japanese Patent Provisional Publication No. 50-43633. Of these Publications, the Japanese Utility Model Provisional Publication No. 57-47477 discloses a safety arrangement as shown in FIGS. 9 and 10 of the drawings of the present application. This safety arrangement is mounted in a passenger compartment and located opposite to a driver's seat. The safety arrangement includes a supporting member 103 which is adapted to support a steering column 101 to a vehicle body 105 in a manner to be movable forward and rearward relative to the vehicle. A knee protector 107 is fixed to the intermediate part of the steering column 101 so as to be opposite to the knees of the driver.
With this conventional arrangement, during vehicle collision, an impact energy of the driver's knees is transmitted through the knee protector 107 to the supporting member 103 thereby causing the steering column 101 to move axially forward relative to the vehicle body 105. At this time, impact energy absorption can be accomplished by the impact absorbing member 109, thereby protecting the driver's knees. Besides, since the steering column 101 is withdrawn, the driver's head is prevented from interference with the steering wheel even if his neck is bent as shown in FIG. 10, thereby protecting the driver's upper half body.
In case of a commercial vehicle of the type wherein the driver frequently repeats ride-in and get-off actions, for example, to deliver goods, the vehicle may sometimes run in a condition the driver is not restrained by the seat belt. If a vehicle collision occurs at such a time, the driver's knees will first strike against the knee protector 107 and then his upper half body comes into collision with the steering wheel which is moving after the steering column 101 moves forward upon impact of the knees with the knee protector. Then impact absorption is accomplished by the impact absorbing member 109. However, it is to be noted that impact absorption for the driver's upper half body cannot be accomplished from the beginning of movement of the steering column, but is accomplished in the course of movement of the steering column 101 which movement is caused by the movement of the knee protector 107. This shortens an impact-absorbing stroke or impact-absorbing time. In view of the above, in order to achieve a sufficient impact-absorption under a condition the driver is not restrained by the seat belt, it is required to make the impact absorbing member large-sized; however this degrades freedom of design of the vicinity of an instrument panel provided with a plurality of operational parts.